DNS Rebinding essentially bypasses the Same Origin Policy on web browsers and allows a malicious website to access content on the local network.
Here is a quick presentation on the topic and this tool.

• Make sure that logcat.mysite.xyz points to logcat.py python file
• logcat.mysite.xyz must be enabled for CORS
• rebind.mysite.xyz points to payload.html
• Replace all occurrences of mysite to your test domain. (Use grep mysite -R to view and sed to replace)
• Install python websockets in a virtualenv or just use pipenv install
• Make sure inbound connections to port 80 (logcat,rebind) and 31337 (websockets) are allowed

A dummy apache config is given below

<Directory /home/ubuntu/mysite/dns-rebind/>
Options +ExecCGI
AddHandler cgi-script .py
</Directory>

<VirtualHost *:80>
ServerName logcat.mysite.xyz
DocumentRoot /home/ubuntu/mysite/dns-rebind/
Header always set Access-Control-Allow-Origin "*"
DirectoryIndex logcat.py
</VirtualHost>

<VirtualHost *:80>
ServerName rebind.mysite.xyz
ServerAlias rebind2.mysite.xyz
DocumentRoot /home/ubuntu/mysite/dns-rebind/
DirectoryIndex payload.html
</VirtualHost>

• Send victim to the hosted server address, here rebind.mysite.xyz
• Goto DNS Settings and point rebind.mysite.xyz to internal IP, say 192.168.1.1
• Run python shell.py
• Wait for the connection
• Enjoy the JS Shell
• You can inject builtin navigate(url, method, data) to navigate to a different page.
• navigate(...) saves fetched pages in logcat.log/